No abstract

Summer-diapause and winter-diapause pupae of the onion maggot, Delia antiqua (Diptera: Anthomyiidae), were significantly more cold hardy than nondiapause, prediapause, and postdiapause pupae. Moreover, cold acclimation of nondiapause pupae conferred strong cold hardiness comparable with that of diapause pupae. Differential display analysis revealed that the expression of a gene encoding TCP-1 (the t-complex polypeptide-1), a subunit of chaperonin CCT, in D antiqua (DaTCP-1) is upregulated in the pupae that express enhanced cold hardiness. Quantitative real-time polymerase chain reaction analyses showed that the levels of DaTCP-1 messenger RNA in pupal tissues, brain, and midgut in particular, are highly correlated with the cold hardiness of the pupae. These findings suggest that the upregulation of DaTCP-1 expression is related to enhanced cold hardiness in D antiqua. The upregulation of CCT in response to low temperature in an organism other than the yeast is newly reported.

To understand the complex physiological process underlying pig testis development and spermatogenesis, this study aims to characterize the change in miRNA and mRNA profiles at four developmental stages of embryonic and postnatal testes, including 60 dpc (days post coitus, E60), 90 dpc (E90), 30-day-old (D30) and 180-day-old (D180). A total of 304 mature, 50 novel miRNAs, and 8343 differentiallyexpressed genes were identified. 93 (48 up and 45 down), 104 (49 up and 55 down), 122 (49 up and 73 down) differentially-expressed miRNAs, as well as 1007 (646 up and 361 down), 1929 (911 up and 1018 down), 7420 (3998 up and 3422 down) differentially-expressed genes were identified in E90 vs. E60, D30 vs. E90 and D180 vs. D30, respectively. Integrating analysis of miRNA and mRNA expression profiles predicted more than 50 000 miRNA-mRNA interaction sites. GO and KEGG pathway analysis of the predicted target genes illustrated the likely roles of differentially expressed miRNAs in testis development and spermatogenesis. For example, PI3K-Akt signaling pathway and Hippo signaling pathway related development, and carbon metabolism, fatty acid metabolism, protein digestion and absorption, were involved in metabolite synthesis. These integrated high-throughput expression data show that miRNA is a critical factor in porcine testis development, providing a useful resource to understand global genome expression change in porcine testis development and spermatogenesis.

Methanol synthesis from CO2 hydrogenation with H2 produced from renewable energy has emerged as a promising method for carbon neutrality. The supported Pd/In2O3 catalyst has attracted great attention due to its superior activity and methanol selectivity, but the formation of the In–Pd bimetallic phase upon over-reduction would lead to quick catalyst deactivation. In this work, we elucidate the reduction behavior of Pd/In2O3 catalysts by using TCPP­(Pd)@MIL-68­(In) as precursors. During catalyst fabrication, metalloporphyrins (viz., TCPP­(Pd)) served as both a capping agent for the growth of MIL-68­(In) and a shuttle for transporting the Pd2+, which enhanced the dispersion of Pd0 species on In2O3–x during the calcination and reduction treatments and prevented the formation of In–Pd bimetallic phase by over-reduction. With a low Pd loading of 0.53 wt %, the resultant Pd/In2O3 catalyst exhibited a maximum methanol space–time yield of 81.1 gMeOH h–1 gPd –1 with a CO2 conversion of 8.0% and a methanol selectivity of 81% over 50 h on stream (295 °C, 3.0 MPa, 19,200 mL gcat –1 h–1). In contrast, the comparative Pd/In2O3 catalyst prepared by the impregnation of PdCl2 in MIL-68­(In) showed poor activity and stability due to the formation of InPd/In2O3–x surface structures. In addition, we found a strong connection between the reduced degree of In2O3 and the catalytic performance of the supported Pd/In2O3 catalysts by integrating catalyst characterization results with density functional theory (DFT) calculations. Interestingly, the surface In/O ratio detected by XPS can reflect information about both metal–support interaction and the amount of oxygen vacancy, which is highly related to the catalytic activity. The DFT calculation also shows that the Pd/In2O3 catalyst has excellent thermodynamic selectivity for the CH3OH product. This work provides an alternative synthetic strategy for Pd/In2O3 nanocatalysts and sheds light on the deactivation mechanism of the supported catalysts.

To make "clean" reduced GO sheets in high quality and in large scale, a natural reduced nicotinamine adenine dinucleotide NAD(P)H model, Hantzsch 1,4-dihydropyridine (HEH), is used as a mild organic photoreductant in this work. Benefiting from the intense absorption of HEH in the range of 300-420 nm, the graphene oxide (GO) can be readily reduced by HEH under UV light irradiation (λ > 320 nm) to afford single or few-layer reduced graphene oxide at room temperature. Studies on reduction extent reveal that both irradiation time and concentration ratio of HEH to GO are important for effective reduction of GO under UV light. The as-prepared photochemically reduced graphene oxide (PRGO) dispersion is stable without the need for any polymeric or surfactant stabilizers. Simply by extraction treatment, the "clean" PRGO sheets can be obtained in large quantities, and its conductivity approaches to 4680 S·m(-1) that is the highest value reported by photochemical approaches so far.